Skip to content


tag  jupyter  tips  ai  deep learning  beginner  regression  reinforcement learning  q learning  gym  gymnasium  ardupilot  None  ros2  dds  micro ros  xrce  sitl  plugin  gazebo  garden  SITL  debug  rangefinder  pymavlink  mavros  distance sensor  system_time  timesync  cmake  gtest  ctest  101  cpp  c++  format  fmt  multithreading  spdlog  cyclonedds  eprosima  fastdds  aptly  apt  repository  repo  local  mirror  encryption  pgp  docker  arm  container  state  networking  network  nvidia  python  app  devcontainer  gui  tutorial  volume  mount  compose  multi-stage  stage  docker compose  git  bundle  submodules  github  hooks  pre-commit  lxd  lxc  x11  profile  vscode  marpit  presentation  marp  markdown  mermaid  mkdocs  video  ffmpeg  gstreamer  cheat-sheet  sdp  v4l2loopback  gi  kml  geo  gis  spatial  gdal  ogr  raster  vector  snippets  cheat Sheet  asyncio  event  future  thread  task  click  cli  cupy  numpy  gpu  dataclass  slots  dev container  deb  debian  package  setup  stdeb  project  hydra  yaml  configuration  matplotlib  3d  subplot  open3d  point cloud  template  black  isort  templates  cookiecutter  docs  project document  docstrings  flake8  linter  git-hook  mypy  unittest  pytest  pylint  from a-z  fixture  scope  logging  pytest.ini  mock  parameterize  enum  flag  iterator  generator  yml  logging config  tuple  namedtuple  typing  annotation  generic  literal  protocol  self  typed dict  typevar  pyzmq  zmq  opencv  msgpack  slam  cartographer  slam_toolbox  action  namespace  remap  control2  demo  diff-drive  ignition  ros2_control  effort  velocity  gdb  qos  plugins  msg  node  zero-copy  shm  algorithm  calibration  diff  pid  dev  colcon  colcon_cd  settings  behavior  py_trees  bt  behavior_trees  blackboard  plot  visualization  debugging  diagnostic  DiagnosticTask  diagnostics  tutorials  gst  math  apm  rat_runtime_monitor  bag  rosbag  rosbags  tools  ros  web  rosbridge  vue  binding  discovery  gazebo-classic  launch  spawn  model  cook  camera  sensors  gps  imu  ray  gazebo_ros_ray_sensor  lidar  ultrsonic  range  ultrasonic  gazebo classic  wrench  gz  sdf  world  vscode tips  gazebogz-sim-joint-position-controller-system  bridge  simulation  ros_gz_bridge  ign  xacro  diff_drive  odom  odometry  joint_state  argument  OpaqueFunction  DeclareLaunchArgument  LaunchConfiguration  tmux  nav  nav2  turtlebot  test  rclpy  goal abort  cancel goal  action client  action server  custom messages  executor  MultiThreadedExecutor  SingleThreadedExecutor  param  dynamic-reconfigure  service  client  setup.py  package.xml  parameter  parameters  custom  msgs  executers  pub  sub  rqt  rviz  rviz2  pose  marker  tf2  local_setup  rosdep  package manager  project settings  vcstool  urdf  robot_state_publisher  urdf_to_graphiz  joint  link  zenoh  tags  hands on  webinar  cross-compiler  esp32  nano  jetson  i2c  adafruit  arduino  sensor  mb1202  uart  serial  tfmini  rpi  raspberry pi  arducam  teensy  microros  config  material  workshope  texture  joints  tmuxp  loop device  rootfs  embedded  zah  linux  rm  ubuntu  sudo  sudoers  nopasswd  visudo  udev  key  gpg  sign  commands  update-alternative  dpkg  ip  ss  netstat  snap  deploy  ssh  systemd  socat  udp  tc  mtu  select  robotics  path planning  trajectory  speed  pcl  kalman_filter  kalman  filter  control  code  extensions  remote  json  schema  yocto  poky  qemu  projects  courses to follow  matrix  graphics  rotation  2d  course  vision  drone  quad  uav  design  vrx  buoyancy 

Spawn xacro model


Table of Content

LAB#

  • Spawn xacro model into ign gazebo world
  • View in rviz

project#

├── CMakeLists.txt
├── config
│   └── rviz.rviz
├── launch
│   └── xacro_demo.launch.py
├── models
│   └── basic.xacro
└── package.xml

CMakeLists#

  • Copy launch, models and config file to workspace install folder
CMakeLists.txt
cmake_minimum_required(VERSION 3.8)
project(ign_tutorial)

find_package(ament_cmake REQUIRED)

install(DIRECTORY
 launch
 models
 config
 DESTINATION share/${PROJECT_NAME}
)

ament_package()

launch file#

  • Use gz_sim.launch.py launch from ros_gz_sim package to launch ignition with empty.world
  • Use xacro node from xacro package to parse the urdf.xacro file
  • Use create node from ros_gz_sim package to spawn the urdf
xacro_demo.launch.py
import os
import xacro
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch_ros.actions import Node
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource

PACKAGE_NAME = "ign_tutorial"

def generate_launch_description():
    pkg_ros_gz_sim = get_package_share_directory('ros_gz_sim')
    pkg_demo = get_package_share_directory(PACKAGE_NAME)

    # Parse robot description from xacro
    robot_description_file = os.path.join(pkg_demo, 'models', 'basic.xacro')
    robot_description_config = xacro.process_file(
        robot_description_file
    )
    robot_description = robot_description_config.toxml()
    params = {'use_sim_time': True, 'robot_description': robot_description}

    # Robot state publisher
    robot_state_publisher = Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        name='robot_state_publisher',
        output='both',
        parameters=[params],
    )

    # Gazebo Sim
    gazebo = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(pkg_ros_gz_sim, 'launch', 'gz_sim.launch.py')
        ),
        launch_arguments={'gz_args': '-r empty.sdf'}.items(),
    )

     # Spawn
    spawn = Node(
        package='ros_gz_sim',
        executable='create',
        arguments=[
            '-name', 'basic',
            '-topic', 'robot_description',
        ],
        output='screen',
    )

    rviz_node = Node(
            package='rviz2',
            namespace='',
            executable='rviz2',
            name='rviz2',
            arguments=['-d' + os.path.join(get_package_share_directory(PACKAGE_NAME), 'config', 'rviz.rviz')]
        )

    return LaunchDescription(
        [
            gazebo,
            spawn,
            robot_state_publisher,
            rviz_node
        ]
    )

urdf#

  • Declare world link and fixed join for tf
basic.xacro
<?xml version="1.0"?>
<robot name="basic_xacro"
    xmlns:xacro="http://www.ros.org/wiki/xacro">

    <xacro:property name="height1" value="2" />
    <xacro:property name="mass" value="1" />
    <xacro:property name="width" value="0.1" />

    <material name="orange">
        <color rgba="${255/255} ${108/255} ${10/255} 1.0"/>
      </material>

    <link name="world"/>

    <joint name="fixed" type="fixed">
        <parent link="world"/>
        <child link="link1"/>
    </joint>

    <!-- Base Link -->
    <link name="link1">
        <collision>
            <origin xyz="0 0 ${height1/2}" rpy="0 0 0"/>
            <geometry>
                <box size="${width} ${width} ${height1}"/>
            </geometry>
        </collision>

        <visual>
            <origin xyz="0 0 ${height1/2}" rpy="0 0 0"/>
            <geometry>
                <box size="${width} ${width} ${height1}"/>
            </geometry>
            <material name="orange"/>
        </visual>

        <inertial>
            <origin xyz="0 0 ${height1/2}" rpy="0 0 0"/>
            <mass value="${mass}"/>
            <inertia ixx="${mass / 12.0 * (width*width + height1*height1)}" ixy="0.0" ixz="0.0" iyy="${mass / 12.0 * (height1*height1 + width*width)}" iyz="0.0" izz="${mass / 12.0 * (width*width + width*width)}"/>
        </inertial>
    </link>
</robot>

Dependencies#

  • rviz2
  • ros_gz_sim
  • xacro
  • robot_state_publisher

package.xml#

  • Add the following dependencies
<exec_depend>xacro</exec_depend>
<exec_depend>robot_state_publisher</exec_depend>
<exec_depend>ros_gz_sim</exec_depend>
<exec_depend>rviz2</exec_depend>

rosdep#

# from package root
rosdep install --from-paths . --ignore-src --rosdistro=humble

apt#

sudo apt install ros-humble-ros-gz-sim
sudo apt install ros-humble-xacro
sudo apt install ros-humble-robot-state-publisher
sudo apt install ros-humble-rviz2